1. Field of The Invention
This invention relates to a sealed compressor for use in an air conditioner, a refrigerator or the like.
2. Description of The Related Art
Referring first to FIG. 6, there is shown the structure of a conventional sealed compressor. As illustrated in this figure, a compression portion 2 and a an electrically driving portion 3 for driving the compression portion 2 are provided in an upper part and a lower part of a sealed casing 1, respectively. Further, a driving shaft 4 of the compression portion 2 is formed as serving as an output shaft of the electrically driving portion 3. The driving shaft 4 extends in the vertical direction and is rotatably supported by a main bearing 5 and a secondary bearing 6 which are formed on the upper wall and the lower wall of a bearing frame provided in a lower part of the compression portion 2, respectively. Further, an oil pump for supplying lubricating oil to the compression portion 2 is provided at a lower end of the driving shaft 4. In case of the conventional sealed compressor, a through hole 7 is formed in the driving shaft in the longitudinal direction. Moreover, a rotating body 8 is inserted into the through hole 7. Furthermore, lower end portions of the through hole 7 and the rotating body 8 are immersed in lubricating oil stored in an oil basin of a bottom portion of the casing 1. When the driving shaft 4 rotates, the rotating body 8 is rotated. At that time, the lubricating oil is sucked into the through hole 7 by centrifugal force which is caused by this rotation of the rotating body 8. A part of the lubricating oil sucked into the through hole 7 lubricates and cools the secondary bearing 6 and thereafter flows to an oil exhaust port 9. On the other hand, the principal part of the lubricating oil sucked into the through hole 7 flows to the main bearing 5 and joins the lubricating oil coming from the secondary bearing 6. Then, the lubricating oil is exhausted from the oil exhaust port 9 to the upper part of the casing 1. The exhausted lubricating oil is, then, is returned to the oil basin.
The conventional sealed compressor, however, has a drawback in that if the lubricating oil contains dusts or the like, such lubricating oil is fed to a sliding portion extending from the main bearing to the secondary bearing without removing the dusts or the like from the lubricating oil and as the result the sliding portion may be damaged by the dusts or the like contained in the lubricating oil fed thereto.
The present invention is accomplished to eliminate such drawback of the conventional sealed compressor.
It is, therefore, an object of the present invention to raise the reliability of a sealed compressor (namely, to provide a sealed compressor having high reliability).